This general service project provides diagnostic support for all research protocols conducted by the clinical sections of the NEI and other Institutes that require measurements of visual function or other ophthalmic diagnostic tests. Psychophysical and electrophysiological techniques are used to detect and quantify visual loss due to disorders of the ocular media, uvea, retina, optic nerve, and central visual pathways. Optical and ultrasonographic methods are used to obtain and analyze images of the eye for health and disease.